For diagnosis of various diseases, determination of therapeutic effects, and health care, patients or subjects have to go to a medical institution or medical examination place to have their blood collected from the vein and tested. The patients or subjects, however, have to wait for a long time until they are informed of the test results. The patients or subjects also have to take a leave from work for the test, and require half a day or longer.
A method that allows testing of blood at any time at any place has been reported in which a trace amount of blood is diluted with a buffer containing an internal standard substance, and an unknown amount of a component present in the diluted plasma is quantified from the dilution factor of the internal standard substance (see Patent Literature 1, for example).
Specifically, as a method in which a trace amount of blood is diluted with a predetermined buffer, and a plasma sample component is quantified and enzyme activity is analyzed from the mixed solution in the diluted sample, a method that uses glycerol-3-phosphate or glycerol as an internal standard substance is known (see Patent Literature 2, for example).
For counting of the number of a blood cell component, a method that uses tyramine as the internal standard substance to be diluted is known (see Patent Literature 3, for example).
On the other hand, a method of testing from a trace amount of blood has been reported, which uses filter paper to collect blood (see Patent Literature 4, for example).
The use of a trace amount of blood allows a test to be performed regardless of the time and place, which is expected to contribute to the finding of a presymptomatic stage or the health maintenance.